true

Fundamental Principle
Wave-Particle Duality of Matter: Matter in its finest state is observed as particles (electrons, protons, quarks), but when unobserved (such as moving from place to place) is described by waves of probability.

Derived Principle
De Broglie's Wave Formula: Particles have an associated wavelength given by wavelength = (Planck's constant)/(particle mass x particle speed).

Definitions
DIFFRACTION: The changing of direction of waves to bend around corners and spread as they encounter obstacles.

INTERFERENCE: The canceling and enhancing effect that occurs when two waves move through the same space at the same time.

The following statements are TRUE:

When waves encounter an object, they can 'bend' around the object and change direction (diffraction)!
If waves pass through two adjacent, parallel slits in an obstacle, an interference pattern is formed behind the slits!
Destructive interference occurs when two different waves try to pass through the same place and cancel each other out!
An interference pattern created by waves consists of alternating positions of constructive and destructive interference!
Louis de Broglie proposed that electrons sometimes act like waves with wavelength = (Planck's constant)/(electron mass x electron speed)!
To observe the wave behavior of electrons, the electrons must pass through slits as narrow as the layers of atoms in a piece of nickel or of graphite!
The interference pattern created when electrons pass through a piece of graphite is evidence that electrons behave like waves!
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